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Title: Retinal structure and function in age-related maculopathy
Author: Wood, Ashley
ISNI:       0000 0004 2732 5104
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2011
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Age-related macular degeneration (AMD) is the principle cause of visual loss and blindness in the developed world. As new treatments and therapies are developed the need to better diagnose and then monitor outcomes of treatment has become more important. This thesis evaluates both structural and functional changes that occur in the early stage of AMD, known as age-related maculopathy (ARM), with the aim of determining their diagnostic potential. This thesis also explores the relationship between structural and functional parameters. Twenty four participants with ARM and 26 control participants were recruited. Retinal function was probed using four focal electroretinography (ERG) techniques: the focal cone ERG, focal flicker ERG, ERG photostress test and focal rod ERG. Long wavelength optical coherence tomography (OCT) was used to assess retinal structure, specifically retinal, choroidal and four intra-retinal layer thicknesses at 21 macular locations. These techniques were initially developed and optimised for the detection of AMD related changes. The ability of each parameter to diagnose ARM was assessed. Correlation and linear regression analyses were carried out to identify any relationships between retinal structure and function in healthy controls. Retinal thickness was reduced in participants with ARM at parafoveal locations (~2° eccentricity), but choroid thickness was unaffected. Diagnostically, focal ERG parameters provided better sensitivity and specificity to ARM than OCT measures, with the ERG photostress test providing the best diagnostic potential. No strong relationships were shown between any ERG parameter and any retinal or choroidal layer volume in control participants. Three ERG parameters were shown to be related to specific retinal features of ARM, but the strongest associations were between ERG photostress test recovery and focal cone ERG b-wave implicit time and a diagnosis of wet AMD in the contralateral eye. In conclusion the structural and functional parameters assessed appeared to provide independent information regarding disease status and severity. ERG parameters showed better diagnostic potential than OCT measures. The single most diagnostic parameter was the recovery time constant of the ERG photostress test.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: RE Ophthalmology